1,439 research outputs found
Zn(II), Cu(II), Ni(II) & Co(II) Complexes of N-(Salicylidene)-N'-[2-(salicylaldimine)- benzoyl]hydrazine, the Schiff Base Derived from o-Aminobenzoylhydrazine & Salicylaldehyde
442-44
Properties and occurrence rates of exoplanet candidates as a function of host star metallicity from the DR25 catalog
Correlations between the occurrence rate of exoplanets and their host star
properties provide important clues about the planet formation processes. We
studied the dependence of the observed properties of exoplanets (radius, mass,
and orbital period) as a function of their host star metallicity. We analyzed
the planetary radii and orbital periods of over 2800 candidates from
the latest data release DR25 (Q1-Q17) with revised planetary radii
based on ~DR2 as a function of host star metallicity (from the Q1-Q17
(DR25) stellar and planet catalog). With a much larger sample and improved
radius measurements, we are able to reconfirm previous results in the
literature. We show that the average metallicity of the host star increases as
the radius of the planet increases. We demonstrate this by first calculating
the average host star metallicity for different radius bins and then
supplementing these results by calculating the occurrence rate as a function of
planetary radius and host star metallicity. We find a similar trend between
host star metallicity and planet mass: the average host star metallicity
increases with increasing planet mass. This trend, however, reverses for masses
: host star metallicity drops with increasing planetary
mass. We further examined the correlation between the host star metallicity and
the orbital period of the planet. We find that for planets with orbital periods
less than 10 days, the average metallicity of the host star is higher than that
for planets with periods greater than 10 days.Comment: 14 pages, 13 Figures, Accepted for publication in The Astronomical
Journa
Meat Consumption and Risk of Developing Esophageal Cancer: A Meta-analysis
Background: Meat has been linked as a risk factor for several cancers. Red meat and processed meat specifically have been suggested as risk factors for esophageal cancer, but this has not been established. We performed a meta-analysis to summarize available evidence from case-control and cohort studies on this topic.Methods: A systematic search of MEDLINE, PubMed, EMBASE was completed up until November, 2013. Studies were included that reported confirmed histological diagnosis of cancer, odds ratios (OR) or relative risks (RR) and confidence intervals (CI). Pooled ORs and 95% CIs were calculated for the effect of different meats on the development of esophageal cancer using a random effects model. Studies were assessed for heterogeneity and publication bias.Results: 29 studies were included in this analysis, involving 1,208,768 individuals with a total of 8,620 cases and 44,574 controls. High consumption rates were associated with development of cancer for red meat (OR 1.59; 95% CI 1.31-1.93), processed meat (OR 1.75; 95% CI 1.28-2.38), barbecued meat (OR 1.54; 95% CI 1.25–1.91) and overall (OR 1.26; 95% CI 1.11-1.43). Low and medium consumption rates were also significant for red and barbecued meat. High and medium consumption of white meat was significantly protective. High consumption of fish was also found to be protective (OR 0.73; 95% CI 0.55-0.95).Conclusions: Findings of this meta-analysis demonstrated red meat, processed meat and barbecued meat are likely to increase the risk of esophageal cancer in a dose dependent relationship. Fish and white meat were shown to have a protective effect
Storage Life of an Aluminised HE Composition .
Most high explosive compositions are organic in nature and they tend to undergo slow decomposition during storage under different environmental conditions. The decomposition degrade the molecular stability of the explosive, thereby resulting in reduced performance and service life. The knowledge of decomposition behaviour of the explosive mass determines the storage life of the composition. Hence, change in the chemical stability, sensitivity, mechanical strength and performance are of utmost importance in the prediction of storage life of explosive/ammunitions systems. This paper presents the results on the rate of gas evolution, change in sensitivity, and thermal stability and weight loss of high explosive compositions, viz., Dentex and TNT when exposed to elevated temperature. Based on the collected data, a tentative storage life for the aluminised (Dentex) composition has been computed to be 15 years. The data has been compared with TNT, a standard explosive for assessing the storage life
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